The concealed 3130 series is designed to mount in a 1-3/4" interior doors in medium to high-traffic areas. The single lever arm and roller assembly provides complete concealment. The 3130 series meets ANSI/BHMA A156.4 Grade 1 and the American Disabilities Act (ADA) reduced opening force requirements. A concealed forged steel single-lever arm and a low-friction track and roller assembly for the 3130 Series create optimal door control, with separate regulation of the general closing speed and latching speed. The 3130 Series is UL and cUL listed for self-closing doors without hold-open and carry a 15-year limited warranty. Materials for the closers include a cast iron cylinder, one-piece 1-1/8" forged steel piston, and high-efficiency, full-complement, low-friction bearing. Select closer based on width of door. 3130 Series cylinders available in size 1, 2, or 3.ï¿½ Closing power of 3130 Series closers is not adjustable.